Preparation method and application of Co-NC oxygen reduction catalyst based on loaded FePc

Abstract

The invention discloses a Co-NC oxygen reduction catalyst based on loaded FePc as well as a preparation method and application of the Co-NC oxygen reduction catalyst. The preparation method comprises the following steps: dissolving a cobalt source, a nitrogen source and a carbon source into an acetic acid solution, and uniformly stirring to obtain a mixed solution; standing and freezing the solution to obtain a solid, and freeze-drying the solid to obtain cobalt-based aerogel; placing the cobalt-based aerogel in a tubular furnace, and calcining in an inert atmosphere to obtain a Co-NC catalyst; the preparation method comprises the following steps: dissolving FePc and Co-NC in a DMF (Dimethyl Formamide) solution, stirring, and centrifugally drying to obtain the FePc-loaded Co-NC oxygen reduction catalyst FePc-Co-NC. The prepared FePc-Co-NC catalyst is applied to oxygen reduction reaction, has efficient catalytic activity and good stability, and is expected to be widely applied.

Description

Technical Field

[0001] This invention relates to the field of energy nanomaterials technology, specifically to a method for preparing and applying a FePc-supported Co-NC catalyst. Background Technology

[0002] As the global energy structure shifts towards cleaner energy sources, the development of efficient and stable oxygen reduction reaction (ORR) catalysts is crucial for devices such as fuel cells and metal-air batteries. Currently, commercial applications heavily rely on precious metal catalysts such as platinum (Pt), whose high cost and intrinsic scarcity limit large-scale application.

[0003] Among numerous non-precious metal alternatives, iron phthalocyanine (FePc) has attracted considerable attention due to its well-defined Fe-N4 active center and high theoretical catalytic potential. However, FePc has long faced two inherent drawbacks in practical ORR applications: first, its poor molecular conductivity leads to sluggish charge transport kinetics; second, the strong π-π interactions between molecules easily cause irreversible aggregation during preparation and electrochemical processes, burying and deactivating a large number of active centers.

[0004] To address these issues, existing technologies typically load FePc onto conventional carbon materials (such as carbon black and carbon nanotubes). However, this approach largely relies on physical adsorption and π-π interactions, making it difficult to effectively prevent the migration and aggregation of FePc molecules during long-term reactions. More importantly, conventional carbon supports have very limited ability to regulate the electronic structure of the Fe atoms at the FePc center, failing to fundamentally activate its intrinsic catalytic activity. This results in a bottleneck in improving the performance of the resulting catalysts (especially half-wave potential and long-term stability).

[0005] Therefore, the key challenge in this field lies in designing and preparing a novel composite support that not only strongly anchors and highly disperses FePc molecules to inhibit aggregation, but also engages in specific electronic interactions with them to directly regulate and optimize the electronic state of the active center, thereby synergistically achieving a significant leap in the intrinsic activity and stability of FePc catalysts. Current technologies have not yet provided an effective solution to this complex problem. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, the present invention aims to provide a method for preparing and applying a Co-NC oxygen reduction catalyst based on supported FePc. In this catalyst, the introduction of Co promotes the highly dispersed existence of FePc in the aerogel-derived carbon material, preserving the central Fe-N4 active structure. Furthermore, through interaction with the Co-NC support, its electronic structure is optimized.

[0007] This invention optimizes the loading state of FePc in carbon materials by pre-introducing a cobalt source into chitosan aerogel, and regulates the catalytic activity of FePc sites through Co, thus successfully preparing a FePc-Co-NC oxygen reduction catalyst based on supported FePc.

[0008] The objective of this invention is achieved by at least one of the following technical solutions.

[0009] This invention provides a method for preparing a FePc-supported Co-NC oxygen reduction catalyst (labeled FePc-Co-NC), comprising the following steps:

[0010] (1) Dissolve the cobalt source, nitrogen source and carbon source in acetic acid solution, mix them evenly to obtain a mixed solution; (2) After the mixed solution obtained in step (1) is left to stand for a period of time, it is placed in a refrigerator and frozen to obtain a solid; (3) The solid obtained in step (2) is freeze-dried under vacuum to obtain cobalt-based aerogel; (4) The cobalt-based aerogel obtained in step (3) is calcined under an inert atmosphere to obtain a Co-NC catalyst; (5) The Co-NC catalyst obtained in (4) and FePc were dissolved in DMF (N,N-dimethylformamide), and after thorough sonication and stirring, the mixture was centrifuged, the precipitate was collected and dried to obtain the FePc-Co-NC oxygen reduction catalyst based on supported FePc.

[0011] Furthermore, in step (1), the cobalt source is either cobalt nitrate (Co(NO3)2·6H2O) or cobalt chloride (CoCl2).

[0012] Further, in step (1), the nitrogen source is urea (CH4N2O) and dicyandiamide (C2H4N4), wherein the mass ratio of urea to dicyandiamide is 2~4:1, preferably, the mass ratio of urea to dicyandiamide is 3:1.

[0013] Furthermore, in step (1), the carbon source is chitosan.

[0014] Furthermore, in step (1), the mass ratio of cobalt source: nitrogen source: carbon source in the mixed solution is 0.2~1.2:3~5:0.8~1.2.

[0015] Further, in step (1), the volume fraction of the acetic acid solution is 1~2%, preferably, the concentration of acetic acid is 2%.

[0016] Furthermore, in step (4), the calcination temperature is 950-1050℃ and the calcination time is 1-3h.

[0017] Furthermore, in step (5), the mass ratio of FePc to Co-NC is 0.1 to 1:1.

[0018] The present invention also provides a Co-NC oxygen reduction catalyst based on supported FePc prepared by the above preparation method.

[0019] This invention also provides the application of the above-mentioned FePc-supported Co-NC oxygen reduction catalyst in electrocatalytic oxygen reduction and oxygen evolution.

[0020] Furthermore, a Co-NC oxygen reduction catalyst based on FePc support is used for the cathode oxygen reduction reaction in a zinc-air battery.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The preparation method provided by the present invention uses environmentally friendly material chitosan as a carbon source and replaces the commonly used precious metal catalysts with transition metal cobalt and FePc composite, which significantly reduces the cost of the catalyst; (2) This invention creatively utilizes cobalt species (such as Co, Co-N) in the Co-NC carrier. x The FePc molecules interact electronically with the active centers of the supported FePc molecules, effectively modulating the electronic structure of the Fe sites and producing a significant synergistic catalytic effect. This effect not only greatly enhances the intrinsic oxygen reduction activity of FePc but also strengthens the stability of the catalyst, far exceeding the effect of simple physical mixing or the use of ordinary carbon supports.

[0022] (3) The catalyst prepared in this invention exhibits a high half-wave potential (0.865 V vs. RHE) and limiting current density in the oxygen reduction reaction, and has good long-term stability. Its performance is superior to that of commercial platinum-carbon catalysts, demonstrating its potential to replace noble metal catalysts. Attached Figure Description

[0023] Figure 1 This is a scanning electron microscope (SEM) image of FePc-Co-NC-1 in Example 1.

[0024] Figure 2 This is a transmission electron microscope (TEM) image of the product FePc-Co-NC-1 obtained in Example 1.

[0025] Figure 3 The image shows the X-ray diffraction (XRD) pattern of the product FePc-Co-NC-1 obtained in Example 1.

[0026] Figure 4 The Fourier transform infrared (FT-IR) spectrum of the product FePc-Co-NC-1 obtained in Example 1 is shown.

[0027] Figure 5 The X-ray photoelectron spectroscopy (XPS) spectra of the product FePc-Co-NC-1 obtained in Example 1 and the catalyst obtained in Comparative Example 3 are shown.

[0028] Figure 6 The graph shows the specific surface area characterization results of the product FePc-Co-NC-1 obtained in Example 1 and the catalysts obtained in Comparative Examples 1-3.

[0029] Figure 7 Linear sweep voltammograms (LSVs) of the oxygen reduction reaction of the FePc-Co-NC products obtained in Examples 1-3.

[0030] Figure 8 Linear sweep voltammograms (LSVs) of the oxygen reduction reaction of FePc-Co-NC products obtained in Examples 1 and 4-7.

[0031] Figure 9 Linear sweep voltammograms (LSVs) of the oxygen reduction reaction of the FePc-Co-NC products obtained in Examples 1, 8, and 9.

[0032] Figure 10 Linear sweep voltammograms (LSVs) of the oxygen reduction reaction of FePc-Co-NC-1 obtained in Example 1 and the catalysts obtained in Comparative Examples 1-3.

[0033] Figure 11 The chronopotential graph of the product FePc-Co-NC-1 obtained in Example 1 over 10000s is shown. Detailed Implementation

[0034] The following examples further illustrate specific implementations of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are those that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0035] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0037] The electrochemical performance characterization (linear voltammetric scan) methods for the catalysts prepared in the following examples and comparative examples are as follows: All electrochemical measurements were performed at room temperature. 4.0 mg of each catalyst prepared in Examples 1-3 and Comparative Examples 1-3 was prepared into 1.0 mL catalyst ink and dropped onto the working electrode surface, with a loading of 0.0204 g / cm³. 2 After drying, the electrode was used as the working electrode, the platinum wire electrode as the counter electrode, and the 3M Ag / AgCl electrode as the reference electrode. Electrochemical tests were performed using an IGS-9030 (manufactured by Guangzhou Yingsi Instrument Co., Ltd.).

[0038] Linear sweep voltammetry (LSV) test: The tests were conducted in 0.1 M KOH, with saturated oxygen and nitrogen gas introduced beforehand. After connecting the three-electrode system, 20 cycles of cyclic voltammetry (CV) were performed to activate the catalyst. Subsequently, linear voltammetry (LSV) was used to measure the properties of the sample at a scan rate of 5 mV·s. -1 The scanning range is 0.178 to 0.138 V vs RHE.

[0039] According to the Nernst equation (E RHE = E Ag / AgCl + 0.059 pH + 0.21) converts the potential in this work into the reversible hydrogen electrode (RHE) potential.

[0040] Example 1 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.592 g), CH4N2O (3 g), C2H4N4 (1 g), and chitosan (1 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was then freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0041] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 2 h. After that, it was allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0042] Take 10 mg Co-NC and 3 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-1.

[0043] In this embodiment, the half-wave potential in the oxygen reduction reaction is 0.865V, and the overpotential in the oxygen evolution reaction is 318mV.

[0044] Example 2 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.592 g), CH4N2O (3 g), C2H4N4 (1 g), and chitosan (1 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was then freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0045] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 2 h. After that, it was allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0046] Take 10 mg Co-NC and 1 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-2.

[0047] Example 3 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.592 g), CH4N2O (3 g), C2H4N4 (1 g), and chitosan (1 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was then freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0048] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 2 h. After that, it was allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0049] Take 10 mg Co-NC and 10 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-3.

[0050] Example 4 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.592 g), CH4N2O (3.2 g), C2H4N4 (0.8 g), and chitosan (1 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was subsequently freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0051] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 950°C at a heating rate of 5°C / min and maintained at 950°C for 2 hours. The temperature was then allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0052] Take 10 mg Co-NC and 3 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-4.

[0053] Example 5 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.592 g), CH4N2O (2.66 g), C2H4N4 (1.33 g), and chitosan (1 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was subsequently freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0054] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1050℃ at a heating rate of 5℃ / min and maintained at 1050℃ for 2 h. The aerogel was then allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0055] Take 10 mg Co-NC and 3 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-5.

[0056] Example 6 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.592 g), CH4N2O (3 g), C2H4N4 (1 g), and chitosan (1 g) were dissolved in 30 mL of 1% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was then freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0057] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 1 h. The temperature was then allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0058] Take 10 mg Co-NC and 3 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-6.

[0059] Example 7 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.592 g), CH4N2O (3 g), C2H4N4 (1 g), and chitosan (1 g) were dissolved in 30 mL of 1% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was then freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0060] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 3 h. The temperature was then allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0061] Take 10 mg Co-NC and 3 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-7.

[0062] Example 8 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.296 g), CH4N2O (2.25 g), C2H4N4 (0.75 g), and chitosan (0.8 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was subsequently freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0063] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 2 h. After that, it was allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0064] Take 10 mg Co-NC and 3 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-8.

[0065] Example 9 The synthesis steps of the FePc-supported Co-NC oxygen reduction catalyst are as follows: Co(NO3)2·6H2O (0.888 g), CH4N2O (3.75 g), C2H4N4 (1.25 g), and chitosan (1.2 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was subsequently freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0066] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 2 h. After that, it was allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0067] Take 10 mg Co-NC and 3 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-Co-NC-9.

[0068] Comparative Example 1 The preparation method of Co-NC catalyst includes the following steps: Co(NO3)2·6H2O (0.592 g), CH4N2O (3 g), C2H4N4 (1 g), and chitosan (1 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was then freeze-dried under vacuum for 48 h to obtain cobalt-based aerogel, which was collected for later use.

[0069] The prepared cobalt-based aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 2 h. After that, it was allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain Co-NC.

[0070] Comparative Example 2 The preparation method of NC catalyst includes the following steps: CH4N2O (3 g), C2H4N4 (1 g), and chitosan (1 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was then freeze-dried under vacuum for 48 h to obtain an aerogel, which was collected for later use.

[0071] The prepared aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 2 h. After that, it was allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain NC.

[0072] Comparative Example 3 The preparation method of FePc-NC catalyst includes the following steps: CH4N2O (3 g), C2H4N4 (1 g), and chitosan (1 g) were dissolved in 30 mL of 2% (v / v) acetic acid aqueous solution and stirred at room temperature to obtain a clear solution. The clear solution was then frozen in a refrigerator for 12 h, and the frozen solid was then freeze-dried under vacuum for 48 h to obtain an aerogel, which was collected for later use.

[0073] The prepared aerogel was placed in a quartz boat and then placed in a tube furnace. Under an argon atmosphere, the temperature was increased to 1000℃ at a heating rate of 5℃ / min and maintained at 1000℃ for 2 h. After that, it was allowed to cool naturally to room temperature. The resulting black solid was collected and thoroughly ground to obtain NC.

[0074] Take 10 mg NC and 3 mg FePc, dissolve them in 40 ml DMF, sonicate for 1 h, stir for 12 h, centrifuge and dry to obtain a black powder, which is FePc-NC.

[0075] Catalyst characterization and performance testing: (1) The morphology of the catalyst prepared in Example 1 was characterized, and the results are as follows: The morphology of the product FePc-Co-NC-1 obtained in Example 1 was characterized using scanning electron microscopy (SEM), and the results are as follows: Figure 1 As shown, the material has an amorphous morphology, a rough surface structure, a large surface area, and abundant reaction sites.

[0076] The morphology of the product FePc-Co-NC-1 obtained in Example 1 was characterized by transmission electron microscopy (TEM), and the results are as follows: Figure 2 As shown, the material morphology consists of amorphous metal particles with obvious dispersion.

[0077] (2) The crystal structure of the catalyst prepared in Example 1 was characterized, and the results are as follows: The crystal structures of the products obtained in Example 1 and Comparative Examples 1-3 were characterized by X-ray diffraction (XRD), and the results are as follows: Figure 3 As shown, FePc-Co-NC-1 exhibits obvious Co metal diffraction peaks, but no obvious FePc crystal diffraction peaks. Combined with the FT-IR results, this indicates that FePc exists in an amorphous and highly dispersed form on the Co-NC support, and its Fe-N4 active centers are fully exposed. In contrast, Comparative Example 3, which did not introduce Co, has obvious FePc diffraction peaks, indicating that the introduction of Co is beneficial to the high dispersion of FePc.

[0078] (3) The catalyst prepared in Example 1 was characterized by chemical bonding, and the results are as follows: The chemical bonds of Example 1 and the obtained product were characterized by Fourier transform infrared spectroscopy (FT-IR), and the results are as follows: Figure 4 As shown, FePc-Co-NC-1 exhibits the infrared absorption peak of FePc, confirming the successful loading of FePc in FePc-Co-NC-1. The figure also shows that FePc-Co-NC retains the main characteristic absorption peaks of the FePc molecule, particularly those located at 1329 cm⁻¹. - ¹ and 745 cm - The peaks near ¹ can be attributed to the vibrations of the phthalocyanine ring and the characteristic vibrations of the Fe-N bond, respectively, indicating that the molecular skeleton of FePc and its Fe-N4 central structure were not destroyed after loading.

[0079] (4) The elemental composition and chemical states of the catalysts prepared in Example 1 and Comparative Example 3 were characterized, and the results are as follows: The surface elemental composition and chemical states of FePc-Co-NC in Example 1 and FePc-NC in Comparative Example 3 were characterized using X-ray photoelectron spectroscopy (XPS). Figure 5As shown, characteristic peaks for Co, Fe, C, and N elements can be observed, indicating the successful synthesis of the FePc-Co-NC-1 catalyst. Compared to the Co-free control sample (FePc-NC), the binding energy of the Fe 2p characteristic peak in the FePc-Co-NC sample shows an observable shift. 3 / 2 The Fe2p region shifts to a lower binding energy level by 0.48 eV. 1 / 2 The energy shift is 0.85 eV towards a lower binding energy. This indicates a significant electronic interaction between the Co-NC support and the FePc molecule, leading to an increase in the electron cloud density at the Fe center, which is beneficial for the catalytic reaction.

[0080] (5) The specific surface area of ​​the catalysts prepared in Example 1 and Comparative Examples 1-3 was characterized, and the results are as follows. The products obtained in Example 1 and Comparative Examples 1-3 were characterized using a BET nitrogen adsorption-desorption test, and the results are as follows: Figure 6 As shown, among all the prepared materials, the introduction of Co can greatly increase the specific surface area of ​​the catalyst, which is beneficial to exposing more active sites of the catalyst and enhancing the catalytic activity of the catalyst.

[0081] (6) The catalysts prepared in Examples 1-3 and Comparative Examples 1-3 were characterized by electrochemical performance testing, and the results are as follows: The electrochemical performance of Examples 1-7 was characterized using a linear voltammetric method. Figure 7 Linear sweep voltammograms (LSVs) of the oxygen reduction reaction of FePc-Co-NC in Examples 1-3 are shown. The results show that the catalysts prepared in Examples 1-3 all have good oxygen reduction catalytic activity under different amounts of FePc added, and the FePc-Co-NC with 3 mg of FePc added in Example 1 has the best catalytic effect. Figure 8 , Figure 9 Linear sweep voltammograms (LSVs) of the FePc-Co-NC oxygen reduction reaction in Examples 1 and 4-9 are shown. The results indicate that the catalyst described in Example 1 exhibits the best oxygen reduction catalytic activity under varying reactant ratios and calcination conditions.

[0082] The electrochemical performance of Example 1 and Comparative Examples 1-3 was characterized using a linear voltammetric method. Figure 10Linear sweep voltammograms (LSVs) of the oxygen reduction reaction (ORR) of FePc-Co-NC-1 in Example 1 and Comparative Examples 1-3 are shown. The results indicate that FePc-Co-NC-1 in Example 1 exhibits the highest ORR catalytic activity. This is attributed to the excellent dispersion of FePc on the surface of Co-NC and the enhanced catalytic performance of the material due to the presence of Co. The FePc-Co-NC-1 catalyst prepared in Example 1 has a half-wave potential of 0.865 V, which is higher than the 0.85 V of commercial platinum-carbon catalysts, and exhibits a half-wave potential of 4.5 mA / cm². 2 Its high limiting current density demonstrates its potential for application in commercial oxygen reduction catalysis and zinc-air batteries.

[0083] The stability of Example 1 was tested at 0.86V using the chronoamperometry method, and the results are as follows: Figure 11 As shown, 93.26% of the current was retained within 10,000 s, demonstrating that FePc-Co-NC has good oxygen reduction catalytic stability.

[0084] The Co-NC support prepared in the above embodiments not only provides a high specific surface area to promote FePc dispersion, but also has cobalt species (such as Co, Co-N) on its surface. x Co can interact electronically with the Fe-N4 active centers in FePc, optimizing the charge distribution of the Fe centers and thus significantly enhancing the intrinsic oxygen reduction catalytic activity of FePc. Examples show that the activity of FePc-Co-NC far exceeds that of FePc-NC without Co and pure Co-NC, demonstrating a unique synergistic catalytic mechanism between Co and FePc. The prepared catalyst exhibits high half-wave potential and limiting current density in the oxygen reduction reaction, demonstrating its excellent oxygen reduction catalytic potential and its potential to replace existing commercial noble metal catalysts.

[0085] The above embodiments are merely preferred embodiments of the present invention and are only used to explain the present invention, not to limit the present invention. Any changes, substitutions, modifications, etc., made by those skilled in the art without departing from the spirit and essence of the present invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a Co-NC oxygen reduction catalyst based on a FePc support, characterized in that, The method comprises the following steps: (1) dissolving a cobalt source, a nitrogen source and a carbon source in an acetic acid solution, mixing uniformly to obtain a mixed solution; (2) placing the mixed solution obtained in step (1) and freezing to obtain a solid; (3) vacuum freeze-drying the solid obtained in step (2) to obtain a cobalt-based aerogel; (4) calcining the cobalt-based aerogel obtained in step (3) in an inert atmosphere to obtain a Co-NC catalyst; (5) dissolving the Co-NC catalyst obtained in step (4) and FePc in a DMF solution, ultrasonicating and stirring, then centrifuging, collecting the precipitate and drying to obtain a FePc-loaded Co-NC oxygen reduction catalyst FePc-Co-NC.

2. The preparation method of a Co-NC oxygen reduction catalyst based on a load FePc according to claim 1, characterized in that, In step (1), the cobalt source is cobalt nitrate or cobalt chloride.

3. The preparation method of a Co-NC oxygen reduction catalyst based on load FePc according to claim 1, characterized in that, In step (1), the nitrogen source is urea and dicyandiamide, wherein the urea: The mass ratio of dicyandiamide is 2-4:

1.

4. The method for preparing a Co-NC oxygen reduction catalyst based on a load FePc according to claim 1, characterized in that, In step (1), the carbon source is chitosan.

5. The method for preparing a Co-NC oxygen reduction catalyst based on a load FePc according to claim 1, characterized in that, In step (1), the mass ratio of the cobalt source:nitrogen source:carbon source in the mixed solution is 0.2-1.2:3-5:0.8-1.

2.

6. The method for preparing a Co-NC oxygen reduction catalyst based on a load FePc according to claim 1, characterized in that, In step (1), the volume fraction of the acetic acid solution is 1-2%; in step (4), the calcination temperature is 950-1050°C, and the calcination time is 1-3h.

7. The method for preparing a load FePc-based Co-NC oxygen reduction catalyst according to claim 1, characterized by, In step (5), the mass ratio of FePc to Co-NC is 0.1-1:

1.

8. A FePc-loaded Co-NC oxygen reduction catalyst prepared by the preparation method of any one of claims 1-7.

9. Use of the FePc-loaded Co-NC oxygen reduction catalyst of claim 8 in electrocatalytic oxygen reduction and oxygen evolution.

10. Use according to claim 9, characterized in that, The FePc-loaded Co-NC oxygen reduction catalyst is used for cathode oxygen reduction reaction in a zinc-air battery.

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